Our overall studies have been concerned with the biosynthesis, metabolism, and function of the polyamines, particularly putrescine and spermidine. In this part of the work we have concentrated on the biosynthesis and function of polyamines in Escherichia coli. We have continued our studies on the specific genes and enzymatic steps involved in the biosynthesis of these amines. Mutants in these genes have been selected, and recombinant DNA plasmids have been constructed. Strains containing these plasmids have been used for the overproduction of the respective enzymes. During the past year we have been particularly interested in the structure and mechanism of one of the enzymes involved in spermidine biosynthesis, namely, adenosylmethionine decarboxylase, which is coded for by the speD gene. We had previously shown that this enzyme contains covalently-linked pyruvate, and this moiety is required for activity; we are now studying the mechanism of formation of this unusual protein component. As part of this study the speD gene and the gene product (adenosylmethionine decarboxylase) are being sequenced, and better recombinant plasmids have been constructed for the overproduction of the enzyme. Antibodies have been prepared for the detection of the enzyme and any proenzyme in minicell preparations. We have also been continuing our studies on the physiological role of these amines, using our mutants that lack all of the biosynthetic pathways. We have shown that polyamines affect the conformation or stability of the protein-synthesizing ribosomal complex in vivo. Studies have continued on the effects of polyamines on the growth of various bacteriophages and on their role in permitting the readthrough of amber mutants.